NEW CAPT OF B747 IS CONCERNED ABOUT EXTENDED OP OF FORWARD FUEL BOOST PUMPS WHEN NO FUEL IS AVAILABLE DUE TO HIGH BODY ANGLE ON MINIMUM FUEL; LOW GROSS WT TKOFS.

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ACFT WAS TO FLY A 1 HR FLT. NO ALTERNATE WAS GIVEN; AND A FUEL LOAD OF 50100 LBS WAS ON BOARD; ESTIMATED BURN WAS 23900 LBS. UPON ROTATION; THE FORWARD LOW FUEL PRESSURE FUEL LIGHT CAME ON IN TANKS #1; #2; #3; AND #4 AND REMAINED ON UNTIL THE ACFT WAS PITCHED OVER OUT OF 10000 FT AND ACCELERATED THROUGH 250 KIAS. IF 1 FORWARD FUEL PUMP IS DEFERRED; A FUEL LOAD IS REQUIRED OF 24250 LBS IN THE BANK IN THAT TANK PER THE MEL. THEN WHY ON TKOF ARE WE BEING GIVEN A TOTAL FUEL LOAD OF ONLY 50000 LBS? IF THIS IS A NORMAL OCCURRENCE ON THIS LEG; THEN SAFETY DICTATES THAT A MINIMUM FUEL LOAD OF 97000 LBS IS THE MINIMUM FUEL LOAD FOR THIS ACFT ON CERTAIN LEGS OR ANY OTHER FLT THAT IS ABOUT 1 HR OF FLT TIME. I TRIED TO FIND SOME INFO ON HOW LONG YOU CAN RUN A MAIN TANK FUEL PUMP UNCOVERED BUT COULD NOT DO SO. I AM ASSUMING THAT RUNNING ALL 4 FORWARD FUEL PUMPS FOR APPROX 12 MINS IS UNACCEPTABLE. THE ONLY REF TO UNCOVERING THE FORWARD FUEL PUMPS IS A GAR AND THE ACFT PITCH IS TO BE LIMITED. THIS IS NOT POSSIBLE ON TKOF AND IF PITCH AND SPD ARE TO BE LIMITED THEN WE WILL NOT BE ABLE TO MAKE THE CLB GRADIENTS REQUIRED FOR THE TKOF OR SIDS.